What key should i use for grabbing and throwing boxes

the left mouse button needs to be used since this is a fps game, but any other key can work

I feel the ‘F’ or ‘E’ or ‘Q’ key would seem to do the job for the grabbing and for the throwing you could just click your mouse.

the clicking needs to be reserved for the gun, any other ideas?

t t t t t t t t t the letter t

Both the gun and the item grabbed can use the same key.

The player that has grabbed the item, meaning the gun would obviously be unequipped, the player can use the mouse click to throw the item, then the gun equips again once the item was thrown, and the player can now click the gun as well to shoot the bullets.

for grabbing ‘E’ or ‘F’ ( You can make it in settings to auto grab by being close to the items )
for throwing ‘Q’ or ‘G’

try to not make the two keys close to each other